Diving Thoughts

The Kansho is one of my favourite dives, primarily because of her engine room.

She was built in 1938 as a passenger / cargo ferry, but was taken over by the Japanese navy and a 3 inch bow gun was fitted. She was used for transporting supplies and was bombed in Kwajalein. Her engine room was damaged and she had to be towed to Truk by the Momokawa Maru. Both ships anchored in the repair anchorage on their arrival and both were sunk in the Hailstone attacks. The Kansho Maru was hit by a torpedo and sank in 40 metres of water. She is upright, with a 20 degree list to port.

We did this as a dusk dive, and as we dropped down in daylight, there was a nice little turtle swimming along the wreck. We headed into the engine room, which is 3 storeys high with ladders leading you down. Following the guide we went through too quickly to see it as much as we wanted, something we corrected later in the week.

Swimming forwards we had a look at the bow gun before heading back to the 4 storey superstructure. We had a good look in a number of rooms including the radio room and the galley. We went up to the navigation deck where there is a well-preserved telegraph. We finished up our safety stops on the funnel, where we inadvertently picked up a spare diver from Fong’s group who had arrived 20 minutes after us. I suppose all divers look the same in the dark!

Kansho Maru

• Displacement: 4,861tons
• Length: 380 feet
• Beam: 52.5 feet
• Engine: 1 diesel engine
• Depth: 8 – 40  m.

Our Dive

• Depth: 35.1 m.
• Time: 54 minutes
• Gas:  Air

Graphic courtesy of Captain Lance Higgs of S.S. Thorfinn.

The Shinkoku is a lovely dive with good coral growth and excellent fish life.

She was built in 1939 as a tanker, and she originally carried oil from the US, before the oil embargo was imposed. She was then converted into a fleet oiler and supported Admiral Nagano’s strike force in the Pearl Harbour attack. She survived two days of Hailstone attacks before being sunk by a torpedo which hit the engine room.

We started on the bridge and visited the infirmary with its operating table. There are a number of rooms off  the infirmary, including bathrooms, and a lot of things to see in the superstructure.

We then headed backwards to the rear part of the ship and headed down through a variety of rooms into the large engine room. We spent some time in there before having a look at the stern gun, then heading back to the bridge. There are 3 telegraphs still upright in the bridge section. Fish life was good, with the ubiquitous blue fin trevally in evidence throughout the dive. Another excellent dive, and rightly regarded as among the best in Truk Lagoon.

Shinkoku Maru

• Displacement: 10,020 tons
• Length: 500 feet
• Beam: 65 feet
• Engine: 1 diesel engine
• Depth: 12 – 40  m.

Our Dive

• Depth: 34.7 m.
• Time: 53 minutes
• Gas:  Nitrox 32

Graphic courtesy of Captain Lance Higgs of S.S. Thorfinn.

The Kiyozumi Maru was built in 1934 as a freighter with passenger accommodation. In November 1941 the navy converted her into an armed raider by adding six inch guns, torpedo launchers and anti-aircraft guns. In 1943 the navy reversed course slightly and she was converted to a transport ship. After being torpedoed she was towed to Truk for repairs, a case of out of the frying pan and into the fire. While being repaired she was bombed and sank on her port side in 30 metres of water.

We swam in through the large torpedo hole into the second hold. From there we went through the superstructure where the engine room was wide open. We passed the rear holds and swam past the stern and onto the hull. On the hull there are a number of artefacts that have been placed there for people to see.

Bicycle in Hold #5. Photo by Lau Wing Kee

Kiyozumi Maru

• Displacement: 6,983 tons
• Length: 450 feet
• Beam: 61 feet
• Engine: 1 diesel engine
• Depth: 10 – 32  m.

Our Dive

• Depth: 27.2 m.
• Time: 54 minutes
• Gas:  Nitrox 32

Graphic courtesy of Captain Lance Higgs of S.S. Thorfinn.

To help celebrate World Ocean Day, Ecovision and the Canadian Chamber of Commerce are hosting a lunch panel discussion on Monday 7th June at the Mira Hong Kong Hotel in TST. In the evening they are also showing Sharkwater, and the special guest will be the film’s director, Rob Stewart.

For more information, go to their website.

I asked Rob for a good wreck for my 600th dive and he certainly delivered. The San Francisco Maru was built in 1919 as a medium freighter. She had been in semi-retirement when the war started, but was used by the Japanese navy for carrying cargo.

She was fully loaded in February 1944 when she was bombed as part of Operation Hailstone. Apparently photographs show her stern on fire. She sank upright in over 60 metres of water. This makes her quite deep, so there is not a lot of coral on her. The water around is generally quite clear and she is a very popular wreck. She is certainly one of my favourites.

Uncle Bill was someone who has helped both Rita and myself over the years and he was well known to several of the people on the trip. Sadly he died last year, and while a keen diver, he had never visited Truk.  So we chose this dive to scatter his ashes on one of the prettiest wrecks in the lagoon.

There is a mooring line which seems to be tied to an anchor line on the port side of the bow. We went down that and swam along the deck from the picturesque bow gun, towards the superstructure. The first hold used to be full of hemispherical mines but unfortunately fishermen have been taking them to use in dynamite fishing. As s a result there are a lot less mines there than I’d seen on previous visits. After that disappointment, we carried on past the second hold, which has a number of trucks and barrels inside.

On the deck just in front of the superstructure are 3 Type 95 “Ha-Go” light tanks. One is on the port side, and two are on the starboard side, where one appears to be mounting the other. They were being carried as deck cargo and must have been thrown about quite violently as the ship sank.

We only had enough bottom time to tour the forward half of the ship, and after too short a time, we had to turn around and head back to the line. It was a great dive on a lovely wreck.

San Francisco Maru

• Displacement: 5,864 tons
• Length: 385 feet
• Beam: 51 feet
• Engine: 1 steam/coal fired engine
• Depth: 40 -60  m.

Our Dive

• Depth: 51.1 m.
• Time: 44 minutes
• Gas:  Air plus Nitrox 50 stage

Graphic courtesy of Captain Lance Higgs of S.S. Thorfinn.

Octopi come in also sorts of shapes and sizes, but the argonaut octopus must be one of the strangest. The females secrete a thin, white shell, which is called a paper nautilus, and it does make them look like a nautilus. They tuck themselves and their eggs into it and drift through the sea. Sometimes these paper nautiluses contain trapped air, and its function has been  a mystery for many years. Some people have argued that the air is trapped accidentally and is a major problem for the octopus.

Julian Finn and Mark Norman have shown that they air is deliberately introduced by the females, and is used to acquire neutral buoyancy, meaning they can keep their position in the water column without having to expend any energy.

You can read more about it here.

The Futagami was a large salvage tug, and was launched in 1939. She carried salvage derricks, as well as pumps and hoses.

She was involved in the unsuccessful attempts to raise the I-169 submarine, which we had dived earlier in the day.

Her sinking seems to be a bit of a mystery, and it may well be that she was scuttled towards the end of the war, perhaps to prevent the Americans taking her over.

We did this at about 5:30 pm as a dusk dive. Dropping in as it was starting to go dark. The stern was in less than 10 metres, and she angles down a slope with her bow at about 30 metres. We started at the stern and swam forwards past the towline tube just aft of the superstructure. Further on was something that looked a bit like a huge bucket, which housed an anti-aircraft gun. There was one on either side. We went past the bridge which has an intact telegraph inside, before having a look at the crew quarters which are near the bow. Heading back past the bridge again, we had a look into the very tight engine room, and finished up in the aft hold, where the thick salvage hose was stored.

This was another very enjoyable dive.

Futagami Fleet Tug

• Displacement: 625 tons
• Length: 131 feet
• Beam: 32 feet
• Engine: 2  coal/oil fired engines
• Depth: 10 – 30  m.

Our Dive

• Depth: 25.5 m.
• Time: 43 minutes
• Gas:  Nitrox 32

Graphic courtesy of Captain Lance Higgs of S.S. Thorfinn.

On my two previous visits I had not dived this wreck. Opinions on it seem to be polarised. Beforehand I was told that it was so badly damaged that it was practically empty and just a shell, which was largely true. I was also told that there were masses of fish on it, and the views looking out of the wreck to the clean, white sand beyond were really pretty, which was also true.  On balance I fall into the second camp, as I  thoroughly enjoyed my dive.

The Kikukawa was a cargo ship and, according to Klaus Lindemann, on 7th October 1943 supplies were being loaded for a garrison in the Marshall Islands when fire broke out. The ship was carrying a large amount of ordinance, and when the fire reached it in the evening there was a massive explosion. The explosion sank the Kikukawa, completely destroying the rear of the ship. It also sank a salvage vessel that was attempting to fight the fires.

The forward part of the Kikukawa is all that is left, and it is almost upside down. Inside is just a huge cavernous interior with some oil drums, some mangled pieces of machinery. As I had been told the views out onto the sand were lovely, and there were masses of fish on the wreck, including two big puffer fish. Andreas spotted a shark outside.

The hull has some ridges on it, which were apparently caused by pressure waves from the explosion. It was an interesting wreck to see, with good fish life. One I would like to do again.

Kikukawa Maru

• Displacement: 3,833 tons
• Length: 354 feet
• Beam: 50 feet
• Depth: 20 – 37  m.

Our Dive

• Depth: 39.3 m.
• Time: 49 minutes
• Gas:  Air

Researchers have captured video footage of thresher sharks using their tails to swat smaller fish. This seems to be part of their hunting strategy. It might also explain why thresher sharks are often caught by their tails on long-lines.

Thresher shark tails can be up to half the length of the shark and until now there has been no documented evidence of why they had evolved to such a size. Recently a team from the Pfleger Institute of Environmental Research in California and the University of Massachusetts in Dartmouth towed 2 baited lines behind a boat. Over 27 separate days they filmed 33 common thresher sharks near the bait. 14 of these sharks attempted to hit the bait, with a success rate of 65%. This seems to confirm that the sharks use their tails to stun their prey, making it easier to catch.

So far this has only been observed in common thresher sharks, but it seems likely that the other two species of threshers use a similar strategy.

There is an article and some video from the BBC’s website.

I’ve been lucky enough to dive with them several times down at Malapascua with Trevor and Andreas of Thresher Shark Divers, from whose website I borrowed the photos above.

The Heian Maru is the largest wreck still in Truk Lagoon. She was built in 1930 as a passenger / cargo liner, but was converted in to a submarine tender. She was sunk on the 2nd day of Operation Hailstone when a torpedo hit her engine room. She now lies on her port side in about 35 metres of water, but because of her size, her starboard side is at 12 metres.

This is a great wreck, and one dive barely scratches the surface of what there is to see. We focused on the central section and the bow, but still only saw a fraction of it. The merchant ships generally follow a similar pattern, with 2 or 3 holds either side of a central superstructure containing the engine room. But the liners have the addition of, in this case, three decks on a much larger superstructure, which makes them more complex from a diving point of view. This, combined with the size of the Heian Maru, made this a wreck we wanted to come back to.

There is a companionway running along the superstructure containing some very long tubes which were periscopes /snorkels for submarines, as you can see in Catheryn’s photo:

Passageway on Heian Maru (Photo: Catheryn Chu)

Since she lies on her side, once you get a bit deeper into the superstructure it can be very dark. We went into the engine room, where there was a skull, a reminder of the loss of life that happened here. From there, we explored more of the superstructure and the upper companionways, before heading round to the forward holds. Finally we came up to the bow, where you can still clearly see the ship’s name in both English and Japanese.

As we headed along the side back to the line, there were a variety of artefacts that have been placed there, as you can see in Catheryn’s photos below:

Wing, phoning home (Photo: Catheryn Chu)

More artefacts on Heian Maru (Photo: Catheryn Chu)

Heian Maru

• Displacement: 11,616 tons
• Length: 510 feet
• Beam: 66 feet
• Engine: 2  diesels
• Depth: 12 – 35  m.

Our Dive

• Depth: 27.8 m.
• Time: 57 minutes
• Gas:  Nitrox 32

Graphic courtesy of Captain Lance Higgs of S.S. Thorfinn.

Day 2 had a submarine theme, with a dive on the I-169 sub, followed by the Heian Maru Submarine tender and the Futagami tug that attempted to raise the I-169.

The I-169 was built for the Japanese navy, and was launched on 15th Feb 1934. She was involved in the attack on Pearl Harbour, but was eventually converted to an underwater transport. She was a large submarine with a long range, which meant that this role suited her.

Since there were no submarine pens at Truk, standard procedure in the event of an air raid was to submerge and sit on the bottom of the lagoon. On 2nd April 1944, while the Captain was ashore,  there was a warning about an impending raid, so the I-169 submerged. Unfortunately in their haste the crew failed to close the main induction valve, and the control room was flooded. This meant that the remaining crew were unable to open the air valves to push the water out of the ballast tanks, leaving the submarine marooned on the bottom of the lagoon.

After the air raid when the I-169 failed to surface, the Japanese brought in the Futagami Fleet Tug to try and find her. They calculated a possible position based on its anchorage and the direction it was facing, and put divers down. When the divers found the submarine, they could hear tapping coming from crewmen who were trapped in the aft section. The divers managed to get cables round the submarine and the Futugami tried to raise her. As they got her up to the surface one of the cables broke and she sank back down again.

They tried lowering air hoses down and drilling holes into the ballast tanks but this didn’t work either, and finally the tapping from inside the wreck stopped as the last crewmen suffocated.

Over the following 6 weeks the Japanese tried to find out why it had sunk, and they apparently recovered 32 bodies. Subsequently they depth charged the wreck to avoid its technology falling into American hands. As a result the bow and conning tower are extensively damaged.

In 1971 divers entered the wreck through an engine room hatch and filmed the interior and the remains of many of the crew. When this film was shown in Japan, the Government commissioned a recovery effort that removed around 70 skulls. The bones were cremated in a Shinto ceremony. Combined with the bodies recovered at the time, it looks as though there were nearly 100 people on board when it sank. This is more than its normal crew of 70, so it’s possible that some shore personnel were helping with loading / unloading at the time.

Several divers have died on this wreck, so the Chuuk Government have banned penetrations, although it would be quite difficult to get inside anyway, and I suspect very narrow and silty if you did.

Joerg about to ascend from the I-169 (Photo: Lau Wing Kee)

We started at the stern and swam forwards past the damaged conning tower. There is a clear reminder of the tragedy, as we could see the cables with which the Japanese tried to raise the submarine. The outer hull is deteriorating, but the inner hull is still intact. There isn’t a lot of coral on the wreck, partly because of its depth, but there was good fish life, including a lot of Moorish Idols and a school of Blue-fin Trevally.

Sutsuki Patrol Boat

• Displacement: 2,440 tons submerged
• Length: 344 feet
• Beam: 27 feet
• Engine: 2 9000 shp diesels plus 2-1800 shp electric motors
• Depth: 40-47 m.

Our Dive

• Depth:40.1 m.
• Time: 44 minutes
• Gas:  Air

Graphic courtesy of Captain Lance Higgs of S.S. Thorfinn.

The Guardian has a series of winning shots from the British Society for Underwater Photographers 2010 competition. The winner in the British and Irish category is the Black-faced blenny shown above. It was taken under Swanage pier in Dorset by Arthur Kingdon.

But there are some other great shots. You can see more on the Guardian’s website. There’s also a write-up on the Telegraph’s website.